A barman who was beaten and burned in a horrific fatal attack had been questioned by police over alleged child indecency weeks before his death, though there is nothing to suggest the inquiry was connected to his murder, police said.

Stuart Walker, 28, from Cumnock, Ayrshire, who died after suffering what detectives described as "horrible injuries", was questioned over an alleged incident involving a 12-year-old boy in August, and a report had been sent to the procurator fiscal.

Strathclyde police said: "There was a report sent to the procurator fiscal in relation to an alleged indecency on a 12-year-old boy. There is no suggestion that this incident is in any way connected to the murder."

Walker's body was discovered shortly before 5am on Saturday at Caponacre industrial estate in Cumnock. He had been at a house party with friends, and left without his glasses and coat, according to local reports.

Detectives have not released details of his injuries, in case it is "prejudicial in the future", but reports have suggested he was beaten and burned before his death.

The force has said there is nothing to suggest Walker, who was gay, was the victim of a homophobic crime, but it was not ruling anything out as no clear motive had been established. Officers do not believe it was a random attack.

The indecency allegation was still being investigated when Walker was murdered but has been closed since his death.

A Crown Office spokesman said: "We can confirm that the procurator fiscal at Ayr received a report concerning a 28-year-old male in connection with an alleged incident on 20 August 2011. The case is now closed."

The murder has shocked the local community and prompted questions both in the Scottish parliament and in the Commons. More than 12,000 people have left messages on Facebook, and thousands have written messages on Twitter.

David Cameron urged the public to help solve the murder after Sandra Osborne, the Labour MP for Ayr, Carrick and Cumnock, raised the case at prime minister's questions. Sending his condolences to Walker's family, he said: "The police cannot solve crimes without the help of the public and I hope everyone will co-operate in the best way they can."

Alex Salmond, the first minister, told the Scottish parliament it was a shocking incident. "The police are responsible for the conduct of the inquiry. They have said publicly that they anticipate a positive conclusion of their inquiries."